Grid for fluidized bed apparatus

ABSTRACT

A flat conical grid at the bottom of a container for forming a fluidized bed therein contains a central opening for granules removal and has a rotary scraper on the upper surface of the grid driven by a shaft extending through the central opening.

- 211 Appl. No.: 260,146

United States Patent [191 Ganiaris Mar. 5, 1974 GRID FOR FLUIDIZED BEDAPPARATUS [75] Inventor:

[73] Assignee: Struthers Scientific and International Corporation, NewYork, N.Y.

[22] Filed: June 6, 1972 I Foreign Application Priority Data June 6,1971 Great Britain............... 28757171 [52] US. Cl. 34/57 D,159/D1G. 3 [51] Int. Cl. F26b 17/10 [58] Field of Search 34/10, 57 R, 57A, 57 D;

159/4 A, 4 CC, 4 VM, DIG. 3 v

[56] References Cited UNITED STATES PATENTS Neophytos Ganiaris,Riverdale, N.Y.

Suzukawa et a1. 34/57 A X 3,711,962 1/1973 ,Fukuyo 34/57 D 3,411,46511/1968 Shirai 3,398,718 8/1968 Pilloton 3,298,792 1/1967 DiDrusco159/D1G. 3

FOREIGN PATENTS OR APPLICATIONS 584,485 10/1959 Canada 159/D1G. 3

Primary Examiner-Meyer Perlin Assistant Examiner-Wil1iam C. Anderson 57ABSTRACT A flatconical grid at the bottom of a container for forming afluidized bed therein contains a central opening for granules removaland has a rotary scraper on the upper surface of the grid driven by ashaft extending through the central opening.

1 Claim, 2 Drawing Figures 1 GRID FOR FLUIDIZED BED APPARATUS BRIEFDESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT Ifthe apparatus of this invention is used as a fluidized bed dryer, blower1 passes air through duct 2 to combustion chamber 3 from which hot airpasses through duct 4 to the bottom compartment 5 of chamber 6'. The hotair passes upward through the perforated grid 7 to rise upward inchamber 6 to form fluidized bed 8 and pass from chamber 6 through duct9. Feed from pipe 10 is introduced into chamber 6 to be sprayed fromheat 11 into bed 8. Feed will then coat the particles of bed 8 andliquid will evaporate therefrom to grow granules. When the granulesreach a given size, they will fall downward onto grid 7.

Grid 7 contains perforations 15 and is formed as a shallow cone with anangle between 6 to 10 with the horizontal. The center of grid 7 containsa central opening 16 about which product pipe 17 extends downward. Avertical shaft 18 passes upward in pipe 17 to have the scraper blades 21fixed thereto. Shaft 18 passes through the sloping bottom wall 19 ofpipe 18 to be driven slowly by motor 20. This rotates blades 21 2 whichscrape large particles from grid 7 to roll down its conical surfacethrough opening 16 to be collected by screw conveyor 22 in tube 23.

This apparatus may be used in other fluidized bed applications as wellas fluidized bed dryers as described. If used as a dryer, it may be usedwith aqueous solutions of ammonium sulphate, ferrous sulphate, orammonium phosphate. The blades 21 prevent any buildup of material ongrid 7 and thus increase the on-line operation time of the dryer.

What is claimed is:

1. In a fluidized bed dryer for granulating particles having a chamber,means passing hot air upward within said chamber, and means introducinga feed into said dryer forming a fluidized bed therein, a productremoval grid comprising, in combination, a perforated grid at the bottomof said chamber, said means passing hot air upward in said chamberpassing the hot air through said grid, said grid having a centralopening and being a flat cone sloping upward at an angle to thehorizontal between 6 and 10 disposed about said central opening, scraperblades radially disposed on the upper surface of said grid, a productremoval pipe extending downward from said central opening in said grid,a shaft extending upward through said product removal pipe and saidcentral opening having said blades mounted thereon, and means rotatingsaid shaft so that said blades scrape large particles from said grid toroll into said opening. a

1. In a fluidized bed dryer for granulating particles having a chamber,means passing hot air upward within said chamber, and means introducinga feed into said dryer forming a fluidized bed therein, a productremoval grid comprising, in combination, a perforated grid at the bottomof said chamber, said means passing hot air upward in said chamberpassing the hot air through said grid, said grid having a centralopening and being a flat cone sloping upward at an angle to thehorizontal between 6* and 10* disposed about said central opening,scraper blades radially disposed on the upper surface of said grid, aproduct removal pipe extending downward from said central opening insaid grid, a shaft extending upward through said product removal pipeand said central opening having said blades mounted thereon, and meansrotating said shaft so that said blades scrape large particles from saidgrid to roll into said opening.